System and method for operating a locomotive parking brake

ABSTRACT

A system for operating a locomotive parking brake includes a wheel brake, a coupling connected to the wheel brake, and means for applying force to the coupling. A sensor connected to the coupling measures a force applied to the coupling and generates a signal reflective of the force applied to the coupling. A method for operating a locomotive parking brake includes applying a force to a coupling connected to a wheel brake, measuring the force applied to the coupling, and comparing the force applied to the coupling to a first predetermined limit. The method further includes indicating that the force applied to the coupling is equal to or greater than the first predetermined limit.

FIELD OF THE INVENTION

The present invention generally involves a system and method for operating a locomotive parking brake. In particular embodiments of the present invention, the system and method may detect and measure the force or tension applied by a take-up device to a wheel brake.

BACKGROUND OF THE INVENTION

Locomotives generally include an air brake system for stopping the locomotive and a separate parking brake system for holding the locomotive in place over long periods. For example, U.S. Pat. Nos. 6,427,811 and 7,347,306, assigned to the same assignee as the present application, disclose various embodiments of parking brakes suitable for use with locomotives. As shown in each patent, the parking brake generally includes a manual or automated take-up device connected by rigging to a brake shoe. The take-up device is often remote from the brake shoe, and operation of the take-up device applies force or tension to the rigging to draw the brake shoe directly against a wheel to prevent the locomotive from moving. The take-up device may be manually operated, for example by using a hand wheel or lever, or a motor may be used to assist in applying the force or tension to the rigging needed operate the parking brake.

A reliable indication of the actual status of the parking brake is important for both equipment and safety reasons. A parking brake that has not been adequately set may allow inadvertent and/or uncontrolled movement of the locomotive. Conversely, a parking brake that has not been adequately released may result in damage to the locomotive wheel and/or parking brake if the locomotive is subsequently moved.

Although various devices and methods have been developed to determine the status and position of the parking brake, the remote location of the take-up device, the potential for interference with the rigging, and the general lack of direct access to the brake shoe individually and collectively can create uncertainty in the parking brake status. For example, the rigging may become bound at some point between the take-up device and the brake shoe. As a result, the amount of force or tension applied by the take-up device and/or rigging may not accurately reflect the amount of force or tension that is actually applied by the brake shoe against the wheel. Therefore, continued improvements in systems and methods for operating a locomotive parking brake would be useful.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention.

One embodiment of the present invention is a system for operating a locomotive parking brake that includes a wheel brake, a coupling connected to the wheel brake, and means for applying force to the coupling. A sensor connected to the coupling measures a force applied to the coupling and generates a signal reflective of the force applied to the coupling.

Another embodiment of the present invention is a system for operating a locomotive parking brake that includes a coupling to the parking brake and a sensor connected to the coupling. The sensor measures a force applied to the coupling and generates a signal reflective of the force applied to the coupling.

The present invention may also include a method for operating a locomotive parking brake that includes applying a force to a coupling connected to a wheel brake, measuring the force applied to the coupling, and comparing the force applied to the coupling to a first predetermined limit. The method further includes indicating that the force applied to the coupling is equal to or greater than the first predetermined limit.

Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:

FIG. 1 is a functional block diagram of a system installed in a locomotive parking brake according to one embodiment of the present invention;

FIG. 2 is a perspective view of the exemplary take-up device shown in FIG. 1; and

FIG. 3 is a functional block diagram of the exemplary brake force sensor shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify position, location, or importance of the individual components unless specifically stated in the claims.

Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

Various embodiments of the present invention provide a system and method for operating a locomotive parking brake 10. As shown in FIG. 1, the system generally includes a wheel brake 12 coupled by a cable or a chain 14 to a take-up device 16. A brake force sensing unit 20 may be installed in line or in series with the cable or chain 14 and proximate to the wheel brake 12. The brake force sensing unit 20 may measure the amount of force or tension applied proximate to the wheel brake 12, compare the measurement to one or more predetermined limits, and/or provide a visual display or indication of the parking brake 10 status based on the comparison. Although various exemplary embodiments of the present invention will be illustrated in the context of a motorized wheel-style parking brake, one of ordinary skill in the art will readily appreciate that the present invention is not limited to any particular parking brake design or style unless specifically recited in the claims, and various embodiments of the present invention may be incorporated into any locomotive parking brake 10.

The wheel brake 12 generally includes a brake disc or brake shoe suitably shaped and sized to engage a complementary surface on a locomotive wheel 22, as shown in FIG. 1. The cable, chain 14, or other linkage may connect the wheel brake 12 to the take-up device 16 through a cantilever 24 so that operation of the take-up device 16 alternately moves the wheel brake 12 toward or away from the locomotive wheel 22. The holding force of the parking brake 10 is directly proportional to the force applied by the wheel brake 12 against the locomotive wheel 22, and industry standards may identify or define a minimum force, above which the parking brake 10 is deemed to be “set”, and a maximum force, below which the parking brake 10 is deemed to be “released.”

FIG. 2 provides a perspective view of the take-up device 16 shown in FIG. 1. The take-up device 16 may include any means for applying force or tension to or through the brake force sensing unit 20 to the wheel brake 12. For example, the means for applying force or tension may include a lever connected through a series of gears and/or sprockets to the cable, chain 14, or other linkage. Repeated strokes of the lever may rotate the gears and/or sprockets to draw up the cable, chain 14, or other linkage, thereby applying force or tension to or through the brake force sensing unit 20 to the wheel brake 12. A suitable lever-style take-up device 14 is more fully described, for example, in U.S. Pat. No. 6,427,811, the entirety of which is incorporated here for all purposes. Alternately, as shown in FIG. 2, the means for applying force or tension may include a hand wheel 26 connected through a series gears 28 and/or sprockets 30 to the cable, chain 14, or other linkage. In this manner, the hand wheel 26 may be manually rotated to turn the gears 28 and/or sprockets 30 to draw up the cable, chain 14, or other linkage, thereby applying force or tension to or through the brake force sensing unit 20 to the wheel brake 12. A suitable wheel-style take-up device 16 is more fully described, for example, in U.S. Pat. No. 7,347,306, the entirety of which is incorporated here for all purposes.

In particular embodiments, the means for applying force or tension to or through the brake force unit 20 may include different and/or additional devices or structures that provide a suitable mechanical advantage in setting and releasing the parking brake 10, and one or ordinary skill in the art will readily appreciate that embodiments of the present invention are not limited to any particular take-up device 16 or means for applying force or tension to or through the brake force sensing unit 20 unless specifically recited in the claims. For example, as shown in FIG. 2, the means for applying force or tension to or through the brake force unit 20 may additionally include a pneumatic, hydraulic, or electric motor 32 connected by an output shaft 34 to the gears 28 and/or sprockets 30. In this manner, the motor 32 may be locally or remotely actuated to drive the gears 28 and/or sprockets 30 to draw up the cable, chain 14, or other linkage, thereby applying force or tension to or through the brake force sensing unit 20 to the wheel brake 12.

FIG. 3 provides a more detailed functional block diagram of the brake force sensing unit 20 shown in FIG. 1. As shown, the brake force sensing unit 20 generally includes a coupling 40, a sensor 42, a processor 44. The coupling 40 is connected in line or in series with the chain 14 and the wheel brake 12 and may be manufactured from any material suitable for connecting to the chain 14 at one end and the wheel brake 12 at the other end. In addition, the coupling 40 may have a shape and size that allow sufficient elastic deformation to facilitate force measurements while not plastically deforming under the maximum anticipated forces. For example, as shown in FIG. 3, the coupling 40 may have a “dog bone” shape to exhibit the desired elastic and strength characteristics suitable for various embodiments of the present invention.

The sensor 42 may any suitable instrument or device known to one of ordinary skill in the art for measuring dynamic forces applied to a structure. For example, the sensor 42 may be a strain gauge attached to the coupling 40 to measure a change in electrical potential or current flow produced by elastic deformation of the coupling 40. As another non-limiting example, the sensor 42 may be a fiber optic cable or interferometer that measures a change in optical frequency associated with elongation of the coupling 40. The sensor 42 may thus measure the force or tension applied to the coupling 40 and generate a signal 46 reflective of the force or tension applied to the coupling 40.

The processor 44 receives the signal 46 reflective of the force or tension applied to the coupling 40. The signal 46 may have a magnitude on the order of millivolts. As a result, the processor 44 is generally located proximate to the sensor 42 to minimize any noise or other electromagnetic interference that might interfere with or distort the signal 46. For example, as shown in FIGS. 1 and 3, the processor 44 may be located inside a casing 48 that shields and protects the coupling 40, sensor 42, processor 44, and associated wiring from the elements and environment proximate to the coupling 40 and/or wheel brake 12.

The processor 44 converts the signal 46 to a force or tension measurement and transmits a digital output 50 for further use by the brake force sensing unit 20 and/or take-up device 16. As shown in FIGS. 1-3, in particular embodiments, the brake force sensing unit 20 may further include a controller 60 remote from the processor 44 and operably connected to the take-up device 16. The controller 60 may receive the digital output 50 from the processor 44 and compare the digital output 50 to one or more predetermined limits associated with a set and/or release condition of the parking brake 10. For example, if the digital output 50 is greater than a first predetermined limit, the comparison will indicate that sufficient force is being applied to the wheel brake 12, and the parking brake 10 is therefore “set.” Conversely, if the digital output 50 is less than a second predetermined limit, the comparison will indicate that very little force is being applied to the wheel brake 12, and the parking brake 10 is therefore “released.” Alternately, or in addition, the controller 60 may include multiple other predetermined limits that provide discreet indications of the amount or degree to which the parking brake 10 is “set” or “released.”

The technical effect of the processor 44 and/or controller 60 is to convert the signal 46 produced by the sensor 42 into a quantity that can then be compared to the one or more predetermined limits. As used herein, the processor 44 and/or controller 60 may include any combination of microprocessors, circuitry, or other programmed logic circuit and are not limited to any particular hardware architecture or configuration. Embodiments of the systems and methods set forth herein may be implemented by one or more general-purpose or customized processors 44 and/or controllers 60 adapted in any suitable manner to provide the desired functionality. The processor 44 and/or controller 60 may be adapted to provide additional functionality, either complementary or unrelated to the present subject matter. For instance, one or more processors 44 and/or controllers 60 may be adapted to provide the described functionality by accessing software instructions rendered in a computer-readable form. When software is used, any suitable programming, scripting, or other type of language or combinations of languages may be used to implement the teachings contained herein. However, software need not be used exclusively, or at all. For example, as will be understood by those of ordinary skill in the art without requiring additional detailed discussion, some embodiments of the systems and methods set forth and disclosed herein may also be implemented by hard-wired logic or other circuitry, including, but not limited to application-specific circuits. Of course, various combinations of computer-executed software and hard-wired logic or other circuitry may be suitable, as well.

The controller 60 may store results of previous comparison between the digital output 50 and the one or more predetermined limits for subsequent review and analysis. For example, the controller 60 may store set and release events by the date, time, and actual force applied for subsequent review and analysis. Alternately or in addition, the controller may display the results of the comparison between the digital output 50 and the one or more predetermined limits on one or more visual indicators 62 shown in FIGS. 1-3. The visual indicators 62 may identify, for example, that power is applied to the brake force sensing unit 20, whether the parking brake 10 is set or released, and/or the presence of any faults in the brake force sensing unit 20. Alternately, or in addition, the visual indicators 62 may include an analog or digital display 64 of the actual force or tension currently being measured by the brake sensing unit 20, as shown in FIGS. 1 and 3.

In particular embodiments, the controller 60 may further selectively enable operation of the take-up device 16 and/or means for applying force to the coupling 40. For example, the controller 60 may enable operation of the motor 32 shown in FIG. 2 to set the parking brake 10 as long as the comparison between the digital output 50 and the first predetermined limit does not indicate that the parking brake 10 is “set.” Once the comparison between the digital output 50 and the first predetermined limit indicates that the parking brake 10 is “set”, the controller 60 may disable or de-energize the motor 32 to prevent excessive force from being applied to the coupling 40 and/or wheel brake 12. In this manner, the controller 60 may reliably ensure that the motor 32 has applied sufficient force or tension to the coupling 40 and wheel brake 12 to ensure that the parking brake 10 holds the locomotive in place.

The particular embodiments described and illustrated in FIGS. 1-3 may also provide a method for operating the locomotive parking brake 10. The method may include, for example, applying a force to the coupling 40 connected to the wheel brake 12, measuring the force applied to the coupling 40, and comparing the force applied to the coupling 40 to a first predetermined limit. The method may further indicate that the force applied to the coupling 40 is equal to or greater than the first predetermined limit or less than the first predetermined limit. In particular embodiments, the method may selectively enable operation of the take-up device 16 based on the comparison between the force applied to the coupling 10 and the first predetermined limit and/or indicate the force applied to the coupling 40.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A system for operating a locomotive parking brake, comprising: a. a wheel brake; b. a coupling connected to the wheel brake; c. means for applying force to the coupling; and d. a sensor connected to the coupling, wherein the sensor measures a force applied to the coupling and generates a signal reflective of the force applied to the coupling.
 2. The system as in claim 1, wherein the means for applying force comprises at least one of a pneumatic, hydraulic, or electric motor.
 3. The system as in claim 1, wherein the sensor comprises at least one of a strain gauge or a fiber optic cable.
 4. The system as in claim 1, further comprising at least one of a cable or chain that connects the means for applying force to the coupling to the coupling.
 5. The system as in claim 1, further comprising a visual indicator operatively connected to the sensor, wherein the visual indicator reflects the force applied to the coupling.
 6. The system as in claim 1, further comprising a processor proximate to the sensor, wherein the processor receives the signal reflective of the force applied to the coupling and generates a digital output.
 7. The system as in claim 6, further comprising a controller remote from the processor, wherein the controller receives the digital output from the processor and compares the digital output to a predetermined limit.
 8. The system as in claim 7, wherein the controller disables operation of the means for applying force to the coupling.
 9. A system for operating a locomotive parking brake, comprising: a. a coupling to the parking brake; and b. a sensor connected to the coupling, wherein the sensor measures a force applied to the coupling and generates a signal reflective of the force applied to the coupling.
 10. The system as in claim 9, further comprising at least one of a pneumatic, hydraulic, or electric motor connected to the coupling.
 11. The system as in claim 9, wherein the sensor comprises at least one of a strain gauge or a fiber optic cable.
 12. The system as in claim 9, further comprising at least one of a cable or chain connected to the coupling.
 13. The system as in claim 9, further comprising a visual indicator operatively connected to the sensor, wherein the visual indicator reflects the force applied to the coupling.
 14. The system as in claim 9, further comprising a processor proximate to the sensor, wherein the processor receives the signal reflective of the force applied to the coupling and generates a digital output.
 15. The system as in claim 14, further comprising a controller remote from the processor, wherein the controller receives the digital output from the processor and compares the digital output to a predetermined limit.
 16. The system as in claim 15, wherein the controller disables operation of the parking brake.
 17. A method for operating a locomotive parking brake, comprising: a. applying a force to a coupling connected to a wheel brake; b. measuring the force applied to the coupling; c. comparing the force applied to the coupling to a first predetermined limit; and d. indicating that the force applied to the coupling is equal to or greater than the first predetermined limit.
 18. The method as in claim 17, further comprising disabling operation of a take-up device based on the comparison between the force applied to the coupling and the first predetermined limit.
 19. The method as in claim 17, further comprising indicating that the force applied to the coupling is less than the first predetermined limit.
 20. The method as in claim 17, further comprising indicating the force applied to the coupling. 